Method and apparatus for forming a guide rib on a section of plastic film

Abstract

A method and apparatus for forming a rib on a section of plastic film utilizes a roll having a groove, extrudes molten polymer into the groove, and places the section of plastic film in contact with the molten polymer in the groove. The molten polymer in the groove is allowed to cool below the melting point thereof while the section of plastic film is in contact with the polymer to cause bonding therebetween and thereby form the rib.

1. An apparatus for forming a rib on a section of plastic film, comprising:
 a roll having a groove; 
 an extrusion die for extruding molten polymer into the groove; and 
 a positioning system comprising a second roll made of a deformable material, wherein the second roll directs the plastic film toward the first-named roll, and wherein the positioning system places the section of plastic film in contact with the molten polymer in the groove such that the molten polymer in the groove is allowed to cool below the melting point thereof while the section of plastic film is in contact with the polymer to cause bonding therebetween and thereby forming the rib. 
 
     
     
       2. The apparatus of  claim 1 , wherein the section of plastic film carries a closure element and wherein the second roll includes a groove that receives the closure element. 
     
     
       3. The apparatus of  claim 1 , wherein the positioning system includes a third roll that presses the section of plastic film against the molten polymer. 
     
     
       4. The apparatus of  claim 3 , wherein the third roll is made of a deformable material. 
     
     
       5. The apparatus of  claim 3 , wherein the section of plastic film carries a closure element and wherein at least one of the first-named, second and third rolls includes a groove that receives the closure element. 
     
     
       6. An apparatus for forming a rib on a section of plastic film, comprising:
 a roll having a groove; 
 an extrusion die for extruding molten polymer into the groove; and 
 a positioning system that places the section of plastic film in contact with the molten polymer in the groove such that the molten polymer in the groove is allowed to cool below the melting point thereof while the section of plastic film is in contact with the polymer to cause bonding therebetween and thereby forming the rib, 
 wherein the section of plastic film carries a closure element and wherein the roll includes a groove that receives the closure element when the section of plastic film is in contact with the polymer. 
 
     
     
       7. The apparatus of  claim 6 , wherein the groove has dimensions larger than dimensions of the closure element. 
     
     
       8. The apparatus of  claim 1 , wherein the positioning system includes an air knife that presses the plastic film against the rib. 
     
     
       9. The apparatus of  claim 1 , wherein the roll is chilled by water. 
     
     
       10. The apparatus of  claim 1 , wherein the positioning system includes an air nozzle that directs an air flow onto the molten polymer before the molten polymer is deposited into the groove. 
     
     
       11. The apparatus of  claim 1 , wherein the extrusion die includes a profile plate wherein the profile plate includes an orifice having a cross-sectional shape similar to a cross-sectional shape of the groove. 
     
     
       12. The apparatus of  claim 11 , wherein the rib has an inverted T-shaped cross-sectional shape. 
     
     
       13. The apparatus of  claim 11 , wherein the rib has a triangular cross-sectional shape. 
     
     
       14. The apparatus of  claim 11 , wherein the rib has a semi-circular cross-sectional shape. 
     
     
       15. The apparatus of  claim 11 , wherein the rib has an inverted Y-shaped cross-sectional shape. 
     
     
       16. The apparatus of  claim 11 , further comprising an air nozzle disposed below the extrusion die. 
     
     
       17. The apparatus of  claim 11 , wherein the roll includes a further groove that receives molten polymer wherein the positioning system places the section of plastic film in contact with the molten polymer in the further groove to form a further rib.